S02E18 - Yellowjacket

A mysterious explosion seemingly kills Hank in his college laboratory, but as the Avengers and their friends mourn the loss of their fallen comrade-in-arms, a fearless new vigilante - endowed with the same powers and technology as Ant-Man/Giant-Man and Wasp and calling himself "Yellowjacket" - begins taking out the members of the Serpent Society.